Objective To study the anti invasive effects and its mechanism and apoptosis induction of pentacyclic triterpenoid including glycyrrhizin (GL), 18β glycyrrhetinic acid (GA), ursolic acid (UA) and oleanolic acid (OA) in highly potentially metastatic lung cancer cell line (PGCL3). Methods The invasive ability, the adhesive ability, the migration ability and the activity of cathepsin B (CB) of PGCL3 cells treated with the four drugs were determined by the invasion test of reconstituted basement membrane, t...